The present invention relates to processes for the catalytic asymmetric reduction of trisubstituted olefins and for the catalytic asymmetric reduction of certain enamines and related compounds.
Processes that economically and efficiently produce enantiomerically enriched organic compounds are of great interest since these compounds are widely used as pharmaceuticals and specialty chemicals. More specifically, reactions that reduce trisubstituted olefins to yield enantiomerically enriched products are commercially quite significant as they can be used in the large scale preparation of pharmaceuticals and specialty chemicals. Thus, the effectiveness and economy of such reduction reactions are important considerations.
Currently utilized methods of producing enantiomerically enriched products by hydrogenation of trisubstituted olefins rely upon the use of expensive late transition metal catalysts such as rhodium and ruthenium. See, Noyori, R. Science 1990, 248, 1194-1199; Ojima, I., et al Tetrahedron 1989, 45, 6901-39. In addition, many types of trisubstituted olefins cannot be efficiently converted, by hydrogenation, to enantiomerically enriched organic compounds using the catalyst systems currently available.
Currently, there are no known methods of producing enantiomerically enriched products by hydrogenation of those enamines and related compounds that are 1,1-disubstituted olefins. Such methods would be useful in many synthesis reactions to provide enantiomerically enriched amines and related enantiomerically enriched compounds.
Accordingly, it would be advantageous to provide more economical and efficient processes for asymmetrically reducing trisubstituted olefins, and to provide an economical and efficient processes for asymmetrically reducing certain enamines and related compounds.
It is thus an object of the invention to provide more economical and effective processes for the asymmetric reduction of trisubstituted olefins. Another object is to provide an effective process to obtain from trisubstituted olefins enantiomerically enriched compounds such as hydrocarbons and functionalized hydrocarbons. It is also an object of the invention to provide economical and effective processes for the asymmetric reduction of enamines that are 1,1-disubstituted olefins. A further object is to provide effective processes to obtain from such enamines enantiomerically enriched amines. Other objects will be apparent upon reading the disclosure that follows.